---
id: CVE-2026-110249
title: >-
  A malicious, compromised, or MITM-controlled Exchange server can return a
  single well-formed SOAP response containing an element with enough attributes
  to keep Thunderbird's main thread CPU-bound for seconds to hours
summary: >-
  A malicious, compromised, or MITM-controlled Exchange server can return a
  single well-formed SOAP response containing an element with enough attributes
  to keep Thunderbird's main thread CPU-bound for seconds to hours. This
  vulnerability …
severity: medium
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T19:30:29.797'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110249'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2077826'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-109/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-110/'
    label: security@mozilla.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110249.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-110249'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2550754'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-110249'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110249'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-110/#CVE-2026-110249'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
ingestedAt: '2026-10-13T19:43:28.944Z'
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cvssSource: vendor
cwe:
  - CWE-770
epss: 0.0018
epssPercentile: 0.0748
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-20T17:01:59.034534Z'
scores:
  vendor: 3.4
  adp: 8.6
---

## Overview

A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10, … · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110249.json)